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Thoroughbred Diesel has been your online performance headquarters since 2002. We know how to get the most performance out of your pickup truck and offer all of today's most popular diesel performance products.

This spring allows you to run higher boost pressures and rpms without experiencing valve float. No extra cylinder head machining is required to run these springs. Depending on installed height, you will have approximately 130# installed pressure.

If you have an aftermarket turbo and are running more rpm than factory, you will see a few problems if you are still using OEM springs. First, valve float, which can cause serious damage to the valvetrain. Second, intake and exhaust valves can be blown open by boost and exhaust drive pressure which allows reversion. Reversion can hurt your power potential by allowing exhaust gasses to enter the cylinder on the intake stroke. Inert gasses in the exhaust, when re-introduced into the cylinder shield the fuel particles from oxygen in the cylinder. This does a few things that negatively affect power.

It increases the time delay from start of injection to start of combustion, it decreases the maximum pressure and maximum temperature reached in the cylinder and it increases the total time needed to completely burn the available fuel. Correct valve spring pressure is a very important piece of power production. If you are running a tuner on an otherwise stock truck with a VGT charger, based on exhaust drive pressure, these springs will help you.